问获取视频中每帧的时间戳

EN

import av
import cv2
import json
import subprocess
import time
from decimal import Decimal
from decord import VideoReader
from ffms2 import VideoSource
from moviepy.editor import VideoFileClip
from typing import List


def with_movie_py(video: str) -> List[int]:
    """
    Link: https://pypi.org/project/moviepy/
    My comments:
        The timestamps I get are not good compared to gMKVExtractGUI or ffms2. (I only tried with VFR video)

    Parameters:
        video (str): Video path
    Returns:
        List of timestamps in ms
    """
    vid = VideoFileClip(video)

    timestamps = [
        round(tstamp * 1000) for tstamp, frame in vid.iter_frames(with_times=True)
    ]

    return timestamps


def with_cv2(video: str) -> List[int]:
    """
    Link: https://pypi.org/project/opencv-python/
    My comments:
        I don't know why, but the last 4 or 5 timestamps are equal to 0 when they should not.
        Also, cv2 is slow. It took my computer 132 seconds to process the video.


    Parameters:
        video (str): Video path
    Returns:
        List of timestamps in ms
    """
    timestamps = []
    cap = cv2.VideoCapture(video)

    while cap.isOpened():
        frame_exists, curr_frame = cap.read()
        if frame_exists:
            timestamps.append(round(cap.get(cv2.CAP_PROP_POS_MSEC)))
        else:
            break

    cap.release()

    return timestamps


def with_pyffms2(video: str) -> List[int]:
    """
    Link: https://pypi.org/project/ffms2/
    My comments:
        Works really well, but it doesn't install ffms2 automatically, so you need to do it by yourself.
        The easiest way is to install Vapoursynth and use it to install ffms2.
        Also, the library doesn't seems to be really maintained.

    Parameters:
        video (str): Video path
    Returns:
        List of timestamps in ms
    """
    video_source = VideoSource(video)

    # You can also do: video_source.track.timecodes
    timestamps = [
        int(
            (frame.PTS * video_source.track.time_base.numerator)
            / video_source.track.time_base.denominator
        )
        for frame in video_source.track.frame_info_list
    ]

    return timestamps


def with_decord(video: str) -> List[int]:
    """
    Link: https://github.com/dmlc/decord
    My comments:
        Works really well, but it seems to only work with mkv and mp4 file.
        Mp4 file can have a +- 1 ms difference with ffms2, but it is acceptable.

    Parameters:
        video (str): Video path
    Returns:
        List of timestamps in ms
    """
    vr = VideoReader(video)

    timestamps = vr.get_frame_timestamp(range(len(vr)))
    timestamps = (timestamps[:, 0] * 1000).round().astype(int).tolist()

    return timestamps


def with_pyav(video: str) -> List[int]:
    """
    Link: https://pypi.org/project/av/
    My comments:
        I don't know why, but sometimes it simply doesn't work with certain video.
        Also, I tested with different mp4 file and sometimes it take 8 seconds and sometimes 117 seconds.

    Parameters:
        video (str): Video path
    Returns:
        List of timestamps in ms
    """
    container = av.open(video)
    video = container.streams.video[0]
    av_timestamps = [
        int(frame.pts * video.time_base * 1000) for frame in container.decode(video)
    ]

    container.close()

    return av_timestamps


def with_ffprobe(video_path: str, index: int = 0) -> List[int]:
    """
    Link: https://ffmpeg.org/ffprobe.html
    My comments:
        Works really well, but the user need to have FFMpeg in his environment variables.

    Parameters:
        video (str): Video path
        index (int): Index of the stream of the video
    Returns:
        List of timestamps in ms
    """

    def get_pts(packets) -> List[int]:
        pts: List[int] = []

        for packet in packets:
            pts.append(int(Decimal(packet["pts_time"]) * 1000))

        pts.sort()
        return pts

    cmd = f'ffprobe -select_streams {index} -show_entries packet=pts_time:stream=codec_type "{video_path}" -print_format json'
    ffprobeOutput = subprocess.run(cmd, capture_output=True, text=True)
    ffprobeOutput = json.loads(ffprobeOutput.stdout)

    if len(ffprobeOutput) == 0:
        raise Exception(
            f"The file {video_path} is not a video file or the file does not exist."
        )

    if len(ffprobeOutput["streams"]) == 0:
        raise ValueError(f"The index {index} is not in the file {video_path}.")

    if ffprobeOutput["streams"][0]["codec_type"] != "video":
        raise ValueError(
            f'The index {index} is not a video stream. It is an {ffprobeOutput["streams"][0]["codec_type"]} stream.'
        )

    return get_pts(ffprobeOutput["packets"])


def main():
    video = r"WRITE_YOUR_VIDEO_PATH"

    start = time.process_time()
    movie_py_timestamps = with_movie_py(video)
    print(f"With Movie py {time.process_time() - start} seconds")

    start = time.process_time()
    cv2_timestamps = with_cv2(video)
    print(f"With cv2 {time.process_time() - start} seconds")

    start = time.process_time()
    ffms2_timestamps = with_pyffms2(video)
    print(f"With ffms2 {time.process_time() - start} seconds")

    start = time.process_time()
    decord_timestamps = with_decord(video)
    print(f"With decord {time.process_time() - start} seconds")

    start = time.process_time()
    av_timestamps = with_pyav(video)
    print(f"With av {time.process_time() - start} seconds")

    start = time.process_time()
    ffprobe_timestamps = with_ffprobe(video)
    print(f"With ffprobe {time.process_time() - start} seconds")


if __name__ == "__main__":
    main()

With Movie py 0.65625 seconds
With cv2 2.4375 seconds
With ffms2 0.0625 seconds
With decord 0.03125 seconds
With av 1.28125 seconds
With ffprobe 0.0 seconds